Apparatus for forming screw-threads.



No. 885,088. )"P'ATENTBD APR. 21,1808. y

E. F. MOY P.'H. 'BASTIB- APPARATUS POR PORMING SCREW THREADS. qu,APPLIGKTION'PILED @18.13. 1907.

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ERNESTIFRANGIS'MOY AND BERCY HENRY lEulS'llE,k OF` LONDON, ENCrLANDfAPPARATUS Fon FORMING soRElW-THREADS.

specification of Lettere Patent. i y Patented Aprirzl, `1908.

Applicationled. April 13, 1907. erial No. 367,971.`

To all whom #may concern:

Be it `known that we, ERNEST. FRANCIS MOY andv PERCY 'HENRY/BASTIE,subjects of the" King of the British Dominions, resid-a ing a't London,En land, have invented cer-y tain new andusefu Improvements in A pa.ratus for Forming Screw-Threads, of W lch the following is aspecification.

i used, raises a-thread by compressing fthe' '.A The meansgenerallyemployed for forming screw-threads on metal or' other suitable sub-lstances may be divided into two types or y usedl comprises dies orchasers for cutting the methods. The type most common groove and leavinga raised-ridge orV thread at a constantangle to the axis oi .thescrewcylinder,l and the other type, less commonly screw blank betweengrooved steel blocks or lby causing it to revolve between yhelieallygrooved rollers Which` must be geared together by 'tooth wheels, so asto turn simul taneously, and atthe same speed. In the latter method theblank cylinder has a diam eter slightl smaller than the finished screw,

thi` threa .beingv formed by displacing 'the surface 'of the metalWithoutl removing any ,particlesandleaving the diameter, as com-Earedwith ythe original blank, smaller at the ottom of'the thread :and`larger at the top of.A

the thread. This system isfonly suitable for forming or vraising threadson ductile metal or substances, suc'h as mild steel, copper or Ourinvention has for its object to simplify the construction of this ty eof screwing-appliance by dispensin wit 1 the use of gear Wheelsfand toprovi e a tool, 'which can be readily adapted to existing screw-makingOur improved apparatus is also constructed sofas to e readi y adjustableto the exact diameter of the screw thread it is desired to form, suchadjustment being also'available to compensate for any wear in ourscrewing mechanism i In the accompanying drawings Figure .l vis fa sideview of a screwing appliance embodyingpur invention, Fi r. 2 is a rearview and Fig. 3 a front vlew of t e sar-ne, Fig. 4 1s a secl tion alongline A-B of Fig. L, Fig.- 5v shows 1 the relative position of thegroovesiorrned in rollers on a largerscale, Fig. 6 is'a'side view andFig. 7 an end view of one of the of the forming rollersl and side Viewof the spindle, and Fig. 9 is an end View ofthe same.

ln carrying our invention into effect we mountupon a suitable toolholder, such as a,

spindles serving as pivotsfor the form-ingA rollers, Fig. 8 is alongitudinal' section of one y parallel to each o ther and at rightangles to the axis ofthe rollers. The grooves are exactly equal in pitchon all the rollers and,are also equ'al to the pitch ofthe screw-threadwe desire to form. I

Therollers are of hardened. steel, mounted on spindles,'sueh as e, f andg, so that they can revolve freely and independently of one another. Thespindles are mounted on the tool holder a 'parallel to each other, andif the grooved rollers are o'f equal diameter, the, spindles are mountedat equal distances from le center'of the holder', such distance beingdetermined by the diameterol the'foiming rollers'and the diameter of thethread to be raised. lf three rollers are em iloyed, they distancebetweenr the end of eac i roller and thercenter ofy the first groovevaries one-third of the' width of a groove, in other words,

the distance between the center of the-irst' Vgroove ofany roller andthe center of the iirst groove of either of the other rollersis eX-actly one-'third ofthe width of agroove, 'as `mdicatedby Fig. 5,whichshows .the three rollers placed side byvside, instead of beingarrangedin a circ1e.

Cf-D indicates aplane through one of the circular ridges 'h of theroller c, at right angles Ito the axis of the, roller and of the toolholder.

As shown by Fig. 5, the corresponding ridges 'L and k of the rollers band d are situated on opposite sides of the plane C-`D `at a distanceequal to one-third ofthe width of a. groove.

The rear endof cach slpindle is mounted in .a cyllndrical head or lhoend isheld in an annular' disk' or ring Z fixed to the headA a by meansof stays m at'equal distances apart.

The o eration of forming a screw-thread onducti e metals or othersuitable materials is carried out by forcing a cylindrical bar or 10oder a, and-'the iront J blank cylinder of the material betweenl the l'grou of grooved rollers parallelto the-.taxes on W eh they are free torevolve 4and in a line with the center or axis of the tool holder.Either the blank or the tool holder with its set of forming rollers isturned on its axis by suitable means, and if the blank is of the correctdiameter and the distance between the forming rollers is properly adpisted, a screw thread will be produced `equa in pitch-to the itch ofthe grooves on the rollers. The. diferent grooved rollers must bearranged in their proper order in regard to position of groovesaccording' 'to the direction of thread re uired -to be formed, that is,whether a rig 1t or left hand thread is desired.

Means are provided for adjusting the distance between the groovedrollers and the axis of the toolholder, in order to obtain exactly thediameter or depth of the screwthread to be formed, and-also tocompensate for wear on the s indles and on the surface of the. vformingrol ers. For this purpose we provide the spindles with eccentricliournals and bearings, as illustrated bv Fig. G, which shows the'spindle c ot' the roller fl, with the eccentric rea-r part c1 passingthrough the head al of the holder, and the eccentric gournal e2 held inthe guide ring l. The rear end of each spindle projects to the rear ofthe` head aand'has a pair of diamctrical holes c e* at right anglestoeachother, inorder to insert a pin, by means oizwhich the spindles mapbe turned on the. axis of the rear part el an( thereby tlici- )art 'ecarrying the roller caused to approac 1 or recede from the axis of theholder. After the desired ad`ustment of the spindles, the r al'e securedin their position by means of adjusting screws n, o, p, and screw-nutsq, 1', s. 'lhe axis ot' each adjusting screw is approximately tangentialto the circuinferenceI of the corresponding spindle, and thecircumference of the screw has a recess to lit the circumference of theslpindle.

also serres for iixing thetool in a lathe or screw-making machine.

1. Mechanism for forming screw-threads by a rolling rocess, com risin aluralit of grooved ro lers mounted) in aiolde lel to the axis of thesame, each roller adapted t0 turn on its axis and having on itscircumference a series of equidistant ridges and grooves at right anglesto the axis of the roller, the portions of the ridges which are nearestto the axis ot the holder arranged in a helical path around the axis of.the holder.

2. Mechanism for forming screw-threads by va rolling process, comprisingthree grooved rollers mounted in a llolder parallel to the axis of thesame, each roller adapted .to turn on its axis and having in itscircumference a series of equidistant `ridges and grooves at rightangles to the axis of the roller, the portions ot the ridges which arenearest to the-axis of thehqlder arranged in a helical path around theaxis of the holder, substantially described 3. Mechanism for formingscrew-threads by a rollingr irocess, comprising a plurality ol' gioovedrollers of equal diameters mounted in a holder parallel to the axis ofthe same at equal distances from the said axis, each roller adapted toturn on its axis and having on its circumference a series of equidistantridges and grooves at right angles to the axis of the roller, theportions of the ridges which are nearest to the axis of the holderarraneed.

in a helical path around the axis of the holder. In testimony whereof wehave set our hands hereunto in the presence of two subscribingwitnesses.

ERNEST FRANCIS MOY. PERGY HENRY BASTIE.

Witnesses EUs'rAon ll. Banaan, JOHN J. Nnwroa'r.

